A Youtuber has managed the performance of playing in 8K at Battlefield 1 thanks to 4 Nvidia Titan Xp in SLI, a 6950X clocked at 4.3 GHz, 64 Gb RAM, a power supply of 1500 W.
He thus obtains between 80 and 90 frames per second. His screen is a Dell 32-inch 8K.
Price of material:
Titan Xp: $ 5608 ($ 1402 * 4),
Dell 32-inch 8K: $ 4999,
Intel Core i7-6950X: $ 1743,
64 Gb of memory: $ 680,
4-slot GPU motherboard: $ 505,
Power supply 1500 W: $ 395,
At least 13930 dollars, and then you have to add the hard drives, water cooling, desktop block, fans, speakers, mouse, keyboard, headphones, sound card, …
And the cost of electricity consumption if you use the PC regularly: $ 1,700 a year.